1. Field of the Invention
The present invention relates to an elastic wave device including a plurality of elastic wave elements, such as a duplexer, for example, and a manufacturing method thereof.
2. Description of the Related Art
To date, an elastic wave device has widely been used as a duplexer of a cellular phone. For example, Japanese Unexamined Patent Application Publication No. 2010-98551 discloses a duplexer in which an elastic wave element portion forming a transmission filter and an elastic wave element portion forming a reception filter are provided on the same piezoelectric substrate. In Japanese Unexamined Patent Application Publication No. 2010-98551, a shield electrode is provided between the transmission filter section and the reception filter section.
In the duplexer described in Japanese Unexamined Patent Application Publication No. 2010-98551, the shield electrode is formed between the transmission filter and the reception filter. Thereby, electromagnetic field coupling between the transmission filter and the reception filter is suppressed, which is considered to improve isolation characteristics.
The duplexer described in Japanese Unexamined Patent Application Publication No. 2010-98551, however, is incapable of sufficiently suppressing electromagnetic field coupling and still has insufficient isolation characteristics, despite the above-described shield electrode provided thereto.